This application relates to devices, techniques and systems for communications, such as network communications systems.
Communications devices and systems interact and communicate with one another via communication links that connect various communication devices and based on communication protocols that govern communications of data and other information through the communication links. For example, under the Open System Interconnection (OSI) Model, a communications system is subdivided into different layers including: a physical layer (PHY), a data link layer, a network layer, a transport layer, a session layer, a presentation layer and an application layer. The PHY includes physical data channels (or lanes) that provide a data connection between the data link layer and a physical medium, such as optical fibers and copper cables. An aggregated lane physical layer (PHY) can be implemented by bundling together multiple lower bandwidth lanes or channels. For example, an IEEE 802.3 40 Gigabit Ethernet (GbE) PHY can be built by aggregating physically or logically together four 10 GbE PHY channels.
Under OSI, a dedicated Physical Medium Dependent (PMD) sub-layer is provided for Ethernet communications, including proper operation of the aggregated PHY channels or lanes. The PMD can be used to present the aggregated PHY channels as a single port on the management interface with a linear address space spanning different channels. The dedicated PMD sub-layer communicates, collects and meaningfully combines information from individual channels in the aggregation or bundle to operate the aggregated PHY channels as a single channel having higher throughput than each individual PHY channel.
Like reference symbols and designations in the various drawings indicate like elements.